Re: [PATCH 1/2] Documentation: devicetree: m25p80: add "nor-jedec" binding

[Mark Rutland <mark.rutland@arm.com>]

On Thu, Mar 12, 2015 at 10:36:29AM +0000, Rafał Miłecki wrote:
> On 12 March 2015 at 11:19, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Wed, Mar 11, 2015 at 10:57 PM, Brian Norris
> > <computersforpeace@gmail.com> wrote:
> >> diff --git a/Documentation/devicetree/bindings/mtd/m25p80.txt b/Documentation/devicetree/bindings/mtd/m25p80.txt
> >> index 4611aa83531b..1b2997d4cee4 100644
> >> --- a/Documentation/devicetree/bindings/mtd/m25p80.txt
> >> +++ b/Documentation/devicetree/bindings/mtd/m25p80.txt
> >> @@ -3,9 +3,12 @@
> >>  Required properties:
> >>  - #address-cells, #size-cells : Must be present if the device has sub-nodes
> >>    representing partitions.
> >> -- compatible : Should be the manufacturer and the name of the chip. Bear in mind
> >> +- compatible : Should be "nor-jedec" for any SPI NOR flash that can be
> >> +               identified by the JEDEC READ ID opcode (0x95).
> >> +               Additionally, may include a device-specific string consisting of
> >> +               the manufacturer and name of the chip. Bear in mind
> >
> > For the casual reader, this suggests putting "nor-jedec" first, which is not
> > what we want. So I would write it like e.g.
> >
> > "Should be the manufacturer and the name of the chip. Additionally,
> >  should contain "nor-jedec" for any SPI NOR flash that can be
> >  identified by the JEDEC READ ID opcode (0x95)."
> 
> I don't really like above. It suggests using manufacturer,name
> always/in most cases. This is what we want to avoid. Let's use
> "nor-jedec" wherever possible (when dealing with JEDEC compatible
> flashes).

The compatible property is a list. We should have "nor-jedec" in the
list, but a more specific string should come first. If we don't
recognise the more specific string, we'll still recognise nor-jedec, if
we do recognise it then we can do more advacned things with the HW (or
work around errata).

Mark.